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Plug in RCD 230V or 110V transformer

Former Community Member
Former Community Member
I'm curious to see what peoples opinions are on the two different options available for safer power tool use either using 110V tools with a site transformer alone or 230V tools however using these with the plug in RCD. 


I'm aware of the center tapped site transformer splitting the voltage into 55V so there is the arguement that it's only 55V pushing through your body, vs the RCD option, you're exposed to the potentially full 230V but the RCD cuts the supply almost instantly. However this is based on the RCD actually working and detecting a fault and even if it does perhaps even that brief exposure to 230V may be enough for some people to be fatal. Then again 55V maybe enough for some people too to be fatal. 


Thought?


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  • 0
    perspicacious:
     the arguement that it's only 55V pushing through your body,


    I did try and follow the pages of mathematics many years ago that a very clever forum member did, which showed that the actual voltage was lower than 55 V, nearer 45 V from memory. 


    I struggled then, so now I wouldn't even try!


    Regards


    BOD

     


    From what I remember, there was a bit of additional complexity (to do with power factor?), but the worst case came from the 3-phase RLV system - with 110V between lines and so around 63V between L and Earth. Then with a TN system equal sized L and PE conductors the maximum voltage at the point of a L-PE fault will be around half that.


    As I understand it RLV is a UK peculiarity - the rest of the 230V world has never heard of such a thing and just uses 30mA RCDs. As a result of harmonization all the standards deem 230V+RCD as acceptable, but there is still a strong preference for RLV in the UK and many individual sites still insist on it.


       - Andy.


Reply
  • 0
    perspicacious:
     the arguement that it's only 55V pushing through your body,


    I did try and follow the pages of mathematics many years ago that a very clever forum member did, which showed that the actual voltage was lower than 55 V, nearer 45 V from memory. 


    I struggled then, so now I wouldn't even try!


    Regards


    BOD

     


    From what I remember, there was a bit of additional complexity (to do with power factor?), but the worst case came from the 3-phase RLV system - with 110V between lines and so around 63V between L and Earth. Then with a TN system equal sized L and PE conductors the maximum voltage at the point of a L-PE fault will be around half that.


    As I understand it RLV is a UK peculiarity - the rest of the 230V world has never heard of such a thing and just uses 30mA RCDs. As a result of harmonization all the standards deem 230V+RCD as acceptable, but there is still a strong preference for RLV in the UK and many individual sites still insist on it.


       - Andy.


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